Getting alerts 'Device /dev/gptid/<guid> is causing slow I/O on pool <pool>'

ZenithX

Cadet
Joined
Apr 7, 2021
Messages
4
I'm getting the following alert about weekly:
'Device /dev/gptid/<guid> is causing slow I/O on pool Datapool'

Just to be clear I am an absolute layman with this stuff, I just built a pc and put TrueNAS on it (sorry i know).

The alert will clear after a few hours then happen again after an hour then clear then happen again after an hour then clear for about a week. I've been having issues with my Plex streams where it will start buffering constantly (also when the alert is cleared) and I can't find anything else that could be causing that. It's only on disk ADA01. I'm running the following config:

CPU: Intel Core i5-11400
MOBO: Asrock B560M Steel Legend consumer board (I know)
RAM: 32Gb DDR4 3200MT/s
BOOT: 128Gb NVMe SSD
HDD: 5x Seagate 4TB Exos 7E8 ST4000NM000A (=CMR) in RAIDZ2
ARC: 500Gb Samsung 850 Evo
NIC: 10GbE Solarflare SFN6122F Dual-Port

My main purpose for this system is to use it as a Plex server and recently also as backup for other devices using SyncThing.

My main issue is that the error is too vague for a laymen. What am I supposed to do now? The drive works and is only three years old so I don't feel like replacing it yet as I'm not sure it's needed and don't feel like putting strain on the pool. Should I just leave it? Is the drive going to fail? Should I replace it? A tiny bit more info would be nice so I'm steered in the right direction.

My detailed issues with my plex streams are that I can be streaming 50mbit/s content that is not being transcoded (cpu=1%, no gpu) on a 1Gbit/s wired connection and have continuous buffering while this did not happen before, being able to handle even 150-200mbit/s content. Does not matter which high bitrate content is played or on which device, playback is horrible. Note: there are no other streams running in the background. Ever.

I've been looking on forums trying to find what I should do now but haven't found any answers. I did run some tests i saw on forums to try to see what was happening:

Code:
root@TrueNAS[~]# zpool status
  pool: Datapool
 state: ONLINE
status: Some supported and requested features are not enabled on the pool.
        The pool can still be used, but some features are unavailable.
action: Enable all features using 'zpool upgrade'. Once this is done,
        the pool may no longer be accessible by software that does not support
        the features. See zpool-features(7) for details.
  scan: scrub repaired 0B in 1 days 16:28:42 with 0 errors on Mon Jan 29 16:34:58 2024
config:

        NAME                                            STATE     READ WRITE CKSUM
        Datapool                                        ONLINE       0     0 0
          raidz2-0                                      ONLINE       0     0 0
            gptid/372c160f-97de-11eb-acfd-a8a1596f8c29  ONLINE       0     0 0
            gptid/37e90584-97de-11eb-acfd-a8a1596f8c29  ONLINE       0     0 0
            gptid/37e2437d-97de-11eb-acfd-a8a1596f8c29  ONLINE       0     0 0
            gptid/37f1d792-97de-11eb-acfd-a8a1596f8c29  ONLINE       0     0 0
            gptid/3805bf00-97de-11eb-acfd-a8a1596f8c29  ONLINE       0     0 0
        cache
          gptid/f7ece5ec-9e03-11eb-abc5-a8a1596f8c29    ONLINE       0     0 0

errors: No known data errors

  pool: boot-pool
 state: ONLINE
status: Some supported and requested features are not enabled on the pool.
        The pool can still be used, but some features are unavailable.
action: Enable all features using 'zpool upgrade'. Once this is done,
        the pool may no longer be accessible by software that does not support
        the features. See zpool-features(7) for details.
  scan: scrub repaired 0B in 00:00:10 with 0 errors on Sat Feb  3 03:45:10 2024
config:
        NAME        STATE     READ WRITE CKSUM
        boot-pool   ONLINE       0     0     0
          ada0p2    ONLINE       0     0     0


and

Code:
root@TrueNAS[~]# fio --ramp_time=5 --gtod_reduce=1 --numjobs=1 --bs=1M --size=100G --runtime=60s --readwrite=write --name=testfile
testfile: (g=0): rw=write, bs=(R) 1024KiB-1024KiB, (W) 1024KiB-1024KiB, (T) 1024KiB-1024KiB, ioengine=psync, iodepth=1
fio-3.28
Starting 1 process
testfile: Laying out IO file (1 file / 102400MiB)
Jobs: 1 (f=1): [W(1)][8.1%][w=34.5MiB/s][w=34 IOPS][eta 12m:24s]
testfile: (groupid=0, jobs=1): err= 0: pid=5084: Wed Feb  7 23:58:59 2024
  write: IOPS=128, BW=128MiB/s (134MB/s)(7763MiB/60525msec); 0 zone resets
   bw (  KiB/s): min=33801, max=703875, per=100.00%, avg=131876.66, stdev=157535.72, samples=119
   iops        : min=   33, max=  687, avg=128.30, stdev=153.94, samples=119
  cpu          : usr=0.30%, sys=3.24%, ctx=38936, majf=0, minf=1
  IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued rwts : total=0, 7763, 0, 0 short = 0, 0, 0, 0 dropped = 0, 0, 0, 0
     latency : target = 0, window = 0, percentile = 100.00%, depth = 1

Run status group 0 (all jobs) : 
    WRITE: bw = 128MiB/s (134MB/s), 128MiB/s-128MiB/s (134MB/s-134MB/s), io=7763MiB (8140MB), run=60525-60525msec



My gut says either of the following might also have something to do with it:

1. I have recently upgraded from 16Gb to 32Gb of RAM, which is plenty for me. Around this time the issues started but I can't remember if it was before or after.
2. I only recently started using the SyncThing plugin to backup data regularly to the system. I know this can use a lot of IO, but I can't begin to understand why this would also cause issues if the syncing devices are turned off.

Where do I go from here? What do I measure? Test? Attempt? I have no clue. Gratefull for any help and sorry if my issue is too vague, I simply don't know any of this stuff.
 

HoneyBadger

actually does care
Administrator
Moderator
iXsystems
Joined
Feb 6, 2014
Messages
5,062
Hey @ZenithX

I'd start by checking and and reseating the cables and RAM in your system - physical changes inside a system always carry a risk of a bump or nudge causing a marginal connection.

I'd also have a look at the SMART results for the drive with smartctl -a /dev/ada0 and look for any counters that seem amiss.
 

ZenithX

Cadet
Joined
Apr 7, 2021
Messages
4
Hi @HoneyBadger,

I've tried smartctl -a /dev/ada1 (note ada1, the drive I have issues with)

with results:
Code:
After scanning selected spans, do NOT read-scan remainder of disk.
If Selective self-test is pending on power-up, resume after 0 minute delay.

root@TrueNAS[~]# smartctl -a /dev/ada1
smartctl 7.2 2021-09-14 r5236 [FreeBSD 13.1-RELEASE-p9 amd64] (local build)
Copyright (C) 2002-20, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family:     Seagate Exos 7E8
Device Model:     ST4000NM002A-2HZ101
Serial Number:    WS206KR6
LU WWN Device Id: 5 000c50 0d55bf39d
Firmware Version: SN03
User Capacity:    4,000,787,030,016 bytes [4.00 TB]
Sector Sizes:     512 bytes logical, 4096 bytes physical
Rotation Rate:    7200 rpm
Form Factor:      3.5 inches
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ACS-4 (minor revision not indicated)
SATA Version is:  SATA 3.3, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is:    Thu Feb  8 00:49:02 2024 CET
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

General SMART Values:
Offline data collection status:  (0x82) Offline data collection activity
                                        was completed without error.
                                        Auto Offline Data Collection: Enabled.
Self-test execution status:      (   0) The previous self-test routine completed
                                        without error or no self-test has ever
                                        been run.
Total time to complete Offline
data collection:                (  575) seconds.
Offline data collection
capabilities:                    (0x7b) SMART execute Offline immediate.
                                        Auto Offline data collection on/off support.
                                        Suspend Offline collection upon new
                                        command.
                                        Offline surface scan supported.
                                        Self-test supported.
                                        Conveyance Self-test supported.
                                        Selective Self-test supported.
SMART capabilities:            (0x0003) Saves SMART data before entering
                                        power-saving mode.
                                        Supports SMART auto save timer.
Error logging capability:        (0x01) Error logging supported.
                                        General Purpose Logging supported.
Short self-test routine
recommended polling time:        (   1) minutes.
Extended self-test routine
recommended polling time:        ( 372) minutes.
Conveyance self-test routine
recommended polling time:        (   2) minutes.
SCT capabilities:              (0x70bd) SCT Status supported.
                                        SCT Error Recovery Control supported.
                                        SCT Feature Control supported.
                                        SCT Data Table supported.

SMART Attributes Data Structure revision number: 10
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x000f   078   064   044    Pre-fail  Always       -       59311962
  3 Spin_Up_Time            0x0003   094   093   000    Pre-fail  Always       -       0
  4 Start_Stop_Count        0x0032   100   100   020    Old_age   Always       -       97
  5 Reallocated_Sector_Ct   0x0033   100   100   010    Pre-fail  Always       -       0
  7 Seek_Error_Rate         0x000f   081   060   045    Pre-fail  Always       -       22120888709
  9 Power_On_Hours          0x0032   073   073   000    Old_age   Always       -       24098
 10 Spin_Retry_Count        0x0013   100   100   097    Pre-fail  Always       -       0
 12 Power_Cycle_Count       0x0032   100   100   020    Old_age   Always       -       97
 18 Head_Health             0x000b   100   100   050    Pre-fail  Always       -       0
187 Reported_Uncorrect      0x0032   100   100   000    Old_age   Always       -       0
188 Command_Timeout         0x0032   100   100   000    Old_age   Always       -       0
190 Airflow_Temperature_Cel 0x0022   058   048   040    Old_age   Always       -       42 (Min/Max 38/47)
192 Power-Off_Retract_Count 0x0032   100   100   000    Old_age   Always       -       60
193 Load_Cycle_Count        0x0032   100   100   000    Old_age   Always       -       1158
194 Temperature_Celsius     0x0022   042   052   000    Old_age   Always       -       42 (0 20 0 0 0)
195 Hardware_ECC_Recovered  0x001a   008   001   000    Old_age   Always       -       59311962
197 Current_Pending_Sector  0x0012   100   100   000    Old_age   Always       -       0
198 Offline_Uncorrectable   0x0010   100   100   000    Old_age   Offline      -       0
199 UDMA_CRC_Error_Count    0x003e   200   200   000    Old_age   Always       -       0
240 Head_Flying_Hours       0x0000   100   253   000    Old_age   Offline      -       23963h+31m+13.673s
241 Total_LBAs_Written      0x0000   100   253   000    Old_age   Offline      -       33715629816
242 Total_LBAs_Read         0x0000   100   253   000    Old_age   Offline      -       169086378118

SMART Error Log Version: 1
No Errors Logged

SMART Self-test log structure revision number 1
Num  Test_Description    Status                  Remaining  LifeTime(hours)  LBA_of_first_error
# 1  Short offline       Completed without error       00%     24002         -
# 2  Extended offline    Completed without error       00%     23939         -
# 3  Short offline       Completed without error       00%     23834         -
# 4  Short offline       Completed without error       00%     23713         -
# 5  Short offline       Completed without error       00%     23666         -
# 6  Short offline       Completed without error       00%     23498         -
# 7  Extended offline    Completed without error       00%     23371         -
# 8  Extended offline    Completed without error       00%     23337         -
# 9  Extended offline    Completed without error       00%     23196         -
#10  Short offline       Completed without error       00%     23170         -
#11  Short offline       Completed without error       00%     23162         -
#12  Short offline       Completed without error       00%     22994         -
#13  Short offline       Completed without error       00%     22826         -
#14  Short offline       Completed without error       00%     22658         -
#15  Short offline       Completed without error       00%     22490         -
#16  Extended offline    Completed without error       00%     22448         -
#17  Short offline       Completed without error       00%     22322         -
#18  Short offline       Completed without error       00%     22154         -
#19  Short offline       Completed without error       00%     21999         -
#20  Short offline       Completed without error       00%     21831         -
#21  Extended offline    Completed without error       00%     21767         -

SMART Selective self-test log data structure revision number 1
 SPAN  MIN_LBA  MAX_LBA  CURRENT_TEST_STATUS
    1        0        0  Not_testing
    2        0        0  Not_testing
    3        0        0  Not_testing
    4        0        0  Not_testing
    5        0        0  Not_testing
Selective self-test flags (0x0):
  After scanning selected spans, do NOT read-scan remainder of disk.
If Selective self-test is pending on power-up, resume after 0 minute delay.



I will reseat connections when I have time, thank you. This might indeed be the issue because the SATA cables are significantly bent at the ports (no other way)

On a side note: I know what the SMART tests do, but I'm not sure I have configured them correctly. Can you tell from the command's result? If I go to Tasks > SMART tests in the web ui, I can see I have configured the following:
LONG: 0 1 * *
SHORT: 0 * * sun

Thanks.
 

ZenithX

Cadet
Joined
Apr 7, 2021
Messages
4
Just reseated all SATA and my Plex streams are currently running much better again, so that seams to have solved it! Thank you so much. Never thought to check that.
 

Saoshen

Dabbler
Joined
Oct 13, 2023
Messages
46
there are sata cables that are angled in various manners/configurations, you can choose which best suites your case.
 
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